In certain critical activities, such as the piloting of an aircraft or activities involved with flight control, it is desirable to determine when the operator performing these activities is becoming fatigued. Such fatigue, which may be physical or psychological, can, of course, have a serious effect on the judgment and/or reaction speed of the operator. Studies have shown that an individual's motor activities, as evidenced by hand tremor and other hand motions, change in relation to degree of fatigue. Information regarding hand motions can be obtained in a number of known ways, but such information is obviously most reliable and thus useful when gathered without interfering with the normal routine of the subject. Thus, massive, bulky systems as well as systems requiring wires or other direct interconnections with a subject have limited application in situations where the presence of a sensing device or interconnecting wires would curtail normal activities or otherwise affect the results obtained.